mcf5249_lo.s

motorola自己开发的针对coldfire 5272的Dbug bootloader程序

/*
 * File:	mcf5249_lo.s
 * Purpose:	Lowest level routines for mcf5249.
 *
 * Notes:	This file assembles with both Diab and GNU tools
 *
 */

#ifdef _UNDERSCORE_
#define mcf5249_init		_mcf5249_init
#define main				_main
#endif
 
 	.extern ___MBAR;
	.extern	___MBAR2;
	.extern ___SRAM0;
	.extern ___SRAM1;
    .extern ___SP_INIT
    .extern mcf5249_init
    .extern main
 
    .global asm_startmeup
    .global _asm_startmeup
 
    .global cpu_cache_flush
    .global _cpu_cache_flush

	.equ	SRAMsize,0x08000

	.text

/********************************************************************/
/*
 * This is the main entry point upon hard reset.
 */
asm_startmeup:
_asm_startmeup:

	/* Initialize RAMBARs: locate SRAM and validate it */
	move.l	#(___SRAM0 + 0x21),d0
	movec	d0,RAMBAR0
	move.l	#(___SRAM1 + 0x21),d0
	movec	d0,RAMBAR1

	/* Point Stack Pointer into SRAM temporarily */
	move.l	#(___SRAM0 + SRAMsize),sp

	/* Initalize MBARs */
	move.l	#(___MBAR + 1),d0
	movec	d0,MBAR
	move.l	#(___MBAR2 + 1),d0
	.long	0x4e7b0C0E		/* movec d0,MBAR2 */

	/* Initialize mcf5249 periphs, etc */
	jsr		mcf5249_init

	/* Relocate Stack Pointer */ 
	move.l	#___SP_INIT,sp

	/* Jump to the main process */
	jmp		main
	
	bra		.
	nop
	nop
	halt

/********************************************************************/
/*
 * The MCF5249 has Icache only 
 */
cpu_cache_flush:
_cpu_cache_flush:
	nop						/* sync */
	move.l	#0x01000000,d0	/* Invalidate the I-Cache */
	movec d0,cacr
	rts

/********************************************************************/
	.end